Flexible semicrystalline polyamides

ABSTRACT

The invention relates to a composition, and structures having a layer made of said composition, in which the composition is, by weight, the total being 100%:
         50 to 100% of at least one polyamide A1 of formula X.Y/Z or 6.Y2/Z in which:
           X denotes the residues of an aliphatic diamine having from 6 to 10 carbon atoms,   Y denotes the residues of an aliphatic dicarboxylic acid having from 10 to 14 carbon atoms,   Y2 denotes the residues of an aliphatic dicarboxylic acid having from 15 to 20 carbon atoms and   Z denotes at least one unit chosen from the residues of a lactam, the residues of an α,ω-aminocarboxylic acid, the unit X1, Y1 in which X1 denotes the residues of an aliphatic diamine and Y1 denotes the residues of an aliphatic dicarboxylic acid, the weight ratios Z/(X+Y+Z) and Z/(6+Y2+Z) being between 0 and 15%;   
           0 to 40% of a plasticizer;   0 to 50% of an impact modifier; and   0 to 50% of a polyamide A2.

This application claims benefit, under U.S.C. §119(a) of French NationalApplication Number 04.10481, filed Oct. 5, 2004, and also claimsbenefit, under U.S.C. §19(e) of U.S. provisional application 60/632,418,filed Dec. 2, 2004, incorporated herein by reference.

FIELD OF THE INVENTION

The present invention relates to flexible semicrystalline polyamides.They are useful for manufacturing parts, by extrusion or injectionmoulding, that are resistant to the fluids used in motor vehicles and tosolvents.

BACKGROUND OF THE INVENTION

The polyamide nylon-12 (PA-12), because of its remarkable mechanicalproperties and its resistance to petrol, oil and greases is widely usedin motor vehicles and heavy goods vehicles. Because of the developmentsin engines and a change in their environment, there is now a requirementfor thermoplastics that can be used at temperatures of 20 to 30° C.above the operating temperatures of PA-12, while still maintaining goodflexibility, impact strength, chemical resistance and goodconvertibility in extrusion. Polyamides having a higher melting pointthan PA-12 are known, such as for example PA-6, PA-6,6, PA-4,6, PA-6,10,PA-6,12 and PA-10,10. However, the problem not solved at the presenttime is that these pure PAs are not flexible enough.

Patent EP 1 038 921 describes polyamide-based thermoplastic compositionscomprising, by weight:

50 to 99% of a polyamide;

1 to 50% of a catalyzed polyamide;

0 to 40% of a plasticizer;

0 to 60%, preferably 0 to 30%, of a flexible modifier;

the total being 100%.

These compositions are useful for manufacturing, for example, flexiblehoses. The examples relate only to PA-11 and PA-12, but otherhomopolyamides and copolyamides are mentioned in the description.

Patent Application US 2002-0019477 describes, in the examples, mouldingmaterials comprising PA-6,12 with acid end groups, PA-6,12 with amineend groups, a grafted EPR (grafted by maleic anhydride), anethylene/alkyl acrylate/glycidyl methacrylate copolymer and aplasticizer (BBSA). Other homopolyamides and copolyamides are mentionedin the description.

Patent Application US 2002-0082352 describes polyamide-basedcompositions to be used in multilayer structures. The examples describecompositions comprising high-viscosity PA-12, a polyamine/polyamidecopolymer and either a grafted SEBS or a blend of an ethylene/propyleneblock copolymer and of a grafted polypropylene. Other homopolyamides andcopolyamides are mentioned in the description.

Patent Application US 2002-0119272 describes polyamide-basedcompositions to be used in multilayer structures. One of the layerscomprises:

a polyamide chosen from PA-6, PA-6,6 and PA-6/6,6;

a polyamine-polyamide;

optionally, a polyamide chosen from PA-11, PA-12, PA-6,12, PA-10,12 andPA-12,12.

A composition has now been found that is based on a polyamide resultingfrom the chain linking of a diamine having from 6 to 10 carbon atoms, ofa diacid having from 10 to 12 carbon atoms and, optionally, of at leastone monomer chosen from lactams, α,ω-aminocarboxylic acids, diamines anddiacids, this composition being able to be used at temperatures of 20 to30° C. above the operating temperatures of PA-12, while stillmaintaining good flexibility, impact strength, chemical resistance andgood convertibility in extrusion.

SUMMARY OF THE INVENTION

The present invention relates to a composition comprising, by weight,the total being 100%:

-   -   50 to 100% of at least one polyamide A1 of formula X.Y/Z or        6.Y2/Z in which:        -   X denotes the residues of an aliphatic diamine having from 6            to 10 carbon atoms,        -   Y denotes the residues of an aliphatic dicarboxylic acid            having from 10 to 14 carbon atoms,        -   Y2 denotes the residues of an aliphatic dicarboxylic acid            having from 15 to 20 carbon atoms and        -   Z denotes at least one unit chosen from the residues of a            lactam, the residues of an α,ω-aminocarboxylic acid, the            unit X1.Y1 in which X1 denotes the residues of an aliphatic            diamine and Y1 denotes the residues of an aliphatic            dicarboxylic acid, the weight ratios Z/(X+Y+Z) and            Z/(6+Y2+Z) being between 0 and 15%;    -   0 to 40% of a plasticizer;    -   0 to 50% of an impact modifier; and    -   0 to 50% of a polyamide A2.

Advantageously, the inherent viscosity of the polyamide A1 is between0.5 and 2 and preferably between 0.8 and 1.8.

The advantage of these compositions is the low water uptake, which doesnot exceed 3.5% and advantageously 3% by weight. Another advantagecompared with PA-6 is the good zinc chloride resistance.

The proportion of Z is sufficient to lower the crystallinity of thePA-X,Y and of the PA-6,Y2 and to facilitate the addition of plasticizeror of impact modifier, but not too high so as not to obtain acopolyamide having a melting point below that of PA-12.

Advantageously the composition comprises, by weight, the total being100%:

-   -   55 to 100% of at least one polyamide A1,    -   0 to 40% of a plasticizer;    -   0 to 45% of an impact modifier; and    -   0 to 45% of a polyamide A2.

In a preferred embodiment the composition comprises, by weight, thetotal being 100%:

-   -   55 to 100% of at least one polyamide A1,    -   0 to 20% of a plasticizer;    -   0 to 45% of an impact modifier; and    -   0 to 45% of a polyamide A2.

In a preferred embodiment the composition comprises, by weight, thetotal being 100%:

-   -   55 to 100% of at least one polyamide A1,    -   0 to 10% of a plasticizer;    -   0 to 10% of an impact modifier; and    -   0 to 45% of a polyamide A2.

In a more preferred embodiment the composition comprises, by weight, thetotal being 100%:

-   -   55 to 95% of at least one polyamide A1,        -   0 to 20% of a plasticizer;        -   0 to 45% of an impact modifier; and        -   0 to 45% of a polyamide A2,    -    the total of the plasticizer, the impact modifier and the        polyamide A2 being 5 to 45%.

In a more preferred embodiment the composition comprises, by weight, thetotal being 100%:

-   -   55 to 85% of at least one polyamide A1,        -   0 to 20% of a plasticizer;        -   0 to 45% of an impact modifier; and        -   0 to 45% of a polyamide A2,    -    the total of the plasticizer, the impact modifier and the        polyamide A2 being 15 to 45%.

In a more preferred embodiment the composition comprises, by weight, thetotal being 100%:

-   -   55 to 80% of at least one polyamide A1,        -   0 to 20% of a plasticizer;        -   0 to 45% of an impact modifier; and        -   0 to 45% of a polyamide A2,    -    the total of the plasticizer, the impact modifier and the        polyamide A2 being 20 to 45%.

In a more preferred embodiment the composition comprises, by weight, thetotal being 100%:

-   -   55 to 80% of at least one polyamide A1,        -   4 to 20% of a plasticizer;        -   5 to 25% of an impact modifier; and        -   0 to 36% of a polyamide A2,    -    the total of the plasticizer, the impact modifier and the        polyamide A2 being 20 to 45%.

In another preferred embodiment the composition comprises, by weight,the total being 100%:

-   -   70 to 95% of at least one polyamide A1,        -   0 to 20% of a plasticizer;        -   0 to 30% of an impact modifier; and        -   0 to 30% of a polyamide A2,    -    the total of the plasticizer, the impact modifier and the        polyamide A2 being 5 to 30%.

In another preferred embodiment the composition comprises, by weight,the total being 100%:

-   -   70 to 95% of at least one polyamide A1,        -   5 to 20% of a plasticizer;        -   0 to 30% of an impact modifier; and        -   0 to 30% of a polyamide A2,    -    the total of the plasticizer, the impact modifier and the        polyamide A2 being 5 to 30%.

The present invention also relates to the composition of the inventionin the form of a powder and to its use for coating articles. The powdercan be made by cryogenic grinding of pellets or by dissolving pellets inethanol and then precipitated as described in U.S. Pat. No. 4,334,056.This powder is useful in processes for covering an article with a filmarising from the melting of a thin layer of powder deposited beforehandon the article.

At the present time, several industrial processes for covering anarticle by melting a powder exist.

The first process is electrostatic powder coating, which consists incharging the powder with static electricity and in bringing it intocontact with the article to be covered, which is at zero potential. Forexample, the powder is injected into an electrostatic spray gun whichcharges the said powder by the corona effect, by triboelectrification orby a combination of both. The powder thus charged is sprayed onto theobject to be covered, which is at zero potential. According to anotherform of electrostatic powder coating, the article at zero potential isimmersed in a fluidized bed of charged powder. Within the fluidized bedis powder with which it is desired to cover the article. This powder isin the form of small solid particles, for example with a size between0.01 and 1 mm (advantageously between 10 and 200 μm), of any shape,which are in a state of fluidization within the bed owing to thepresence of air or any other gas. The powder may be charged byelectrodes, by the corona effect, or by any device placed inside and/oroutside the fluidized bed in order to charge it by the triboelectriceffect. The article covered with powder is then placed in an oven at atemperature high enough to provide a coating, by melting the powder andcausing a film to be formed.

The second process consists in preheating the object to be covered to atemperature above the melting point of the powder. Once the article ishot, it is immediately immersed in a fluidized bed of the powder, thepowder melts on contact with the hot article and forms a film. A solidcovering is thus provided. This process is also called the“fluidized-bed dip coating” process. The powder paint of the presentinvention can be used in both processes.

By way of example a polyamide 10.10/6 in which the caprolactame is 10%by weight of the 10.10/6 is made by polycondensation, the melting pointis 183° C. and the film of coating can be made under 190° C. It will notbe outside of the invention to add stabilizers against hydrolysis suchas carbidiimides (Stabaxol® made by Rhein Chemie) or any otherstabilizer or usual additives.

The compositions of the invention can also be used in a solvent to makevarnishes or coatings. The article is covered with the solventcontaining the polyamide, then the solvent is recovered and the articleis coated by the polyamide. The solvent can be alcohols or aromaticssuch as butanediol, benzilic alcohol, meta cresol, toluene, phenol,xylene or mixture thereof. More preferred are the PA 6.10/Z blended witha polyamide A2. Preferably A2 is PA 12. Z is advantageously 10 to 15%.The proportions A1/A2 are 60/40 to 70/30 and advantageously around65/35. By way of example a PA 6.10/6.6 in which Z is 15 blended with PA12 such as PA 6.10/6.6 is 65% (by weight) and PA 12 is 35% has a meltingpoint of 155° C. and an inherent viscosity of 0.6 dl/g (deciliters pergram) measured in meta cresol at 20° C. according to ISO 307 (1994). Thecompositions of the invention are soluble between 1 to 30%,advantageously 1-25% by weight in hot solvents. These solutions arestable at ambient temperatures more than 60 days.

The composition of the invention may also contain a thermoplasticpolyolefin such as, for example, HDPE, LDPE or LLDPE.

Advantageously the polyamide A1 is PA-6,y in which 6 denotes theresidues of hexamethylene diamine and y denotes the residues of analiphatic dicarboxylic acid having from 10 to 18 carbon atoms.

More advantageously, the polyamide A1 is PA-6,10 (havinghexamethylenediamine and sebacic acid units), PA-6,12 (havinghexamethylenediamine and dodecanedioic acid units), PA-6,14 (havinghexamethylenediamine and C14 acid units), PA-6,18 ((havinghexamethylenediamine and C18 acid units) and PA-10,10 (having1,10-decanediamine and sebacic acid units).

The present invention also relates to structures comprising a layerconsisting of the above composition. That is to say the structure mayeither be a monolayer, and therefore consisting of a layer of the abovecomposition, or a multilayer, and therefore comprising a layerconsisting of the above composition. This structure is useful for makingdevices for storing or transferring of fluids, in particular in motorvehicles and heavy goods vehicles. The fluids may be, for example,petrol, diesel, hydraulic brake fluid, compressed air for the brakecircuits of heavy goods vehicles, and hydraulic clutch fluid. Theinvention also relates to these devices. Such devices may be tanks,hoses, pipes, containers. These structures may include other layersconsisting of other materials.

One advantage of the compositions of the invention compared with PA-12is the 20 to 30° C. higher operating temperature and the improved heatageing.

Another advantage is that, in a multilayer structure, the composition ofthe invention in which X is hexamethylenediamine and Y is sebacic acidadheres to PA-6 (or blends having a PA-6 matrix) and to EVOH. The EVOHlayer may contain an impact modifier (for example EPR or EPDM,optionally grafted). Thus, in a structure consisting of the followingsuccessive layers (starting with the outer layer):

(1) PA-6,y/PA-6 or a blend having a PA-6 matrix;

(2) PA-6,y/EVOH/PA-6 or a blend having a PA-6 matrix;

(3) PA-6,y/EVOH/PA-6,y;

(4) PA-6,y/PA-6 or a blend having a PA-6 matrix/EVOH/PA-6 or a blendhaving a PA-6 matrix;

(5) PA-6,y/PA-6 or a blend having a PA-6 matrix/EVOH/PA-6 or a blendhaving a PA-6 or a PA-6,y matrix.

It is unnecessary to have a tie layer between the outer layer and thenext layer. However, it is possible to place this tie layer between theouter layer and the next layer in order to reinforce the structure.

The direct adhesion of PA-6,10 to EVOH is, however, effective only ifthe EVOH has a sufficient ethylene content. For the same ethylenecontent of the EVOH, the adhesion to PA-6,10 is greater than to PA-6,12.To be able to use EVOHs with a low ethylene content, it will bepreferred to use the structure (4) or the structure (5).

DETAILED DESCRIPTION OF THI

With regard to the polyamide A1 and firstly “X”, the diamine may be astraight-chain α,ω-diamine. It may be branched or a mixture of a linear(straight chain) diamine and of a branched diamine.

With regard to “Y”, the diacid may be a straight-chain α,ω-diacid. Itmay be branched or a mixture of a linear (straight chain) diacid and ofa branched diacid. Advantageously Y contains from 10 to 12 carbon atoms.

With regard to “Z”, its proportion is sufficient to lower thecrystallinity of the PA-X,Y and to make it easier to add plasticizer orimpact modifier, but not too high so as not to obtain a copolyamidehaving a melting point below that of PA-12. This proportion is at most15%, however, depending on the nature of the constituents of Z, it mayvary—a person skilled in the art can readily check the lowering of thecrystallinity by carrying out a DSC (differential scanning calorimetry)measurement on the PA-X,Y and then on the PA-X,Y/Z. Advantageously, theproportion of Z is between 0 and 10% and preferably between 1 and 5%.The lactam may be chosen from caprolactam and lauryllactam. The numberof carbon atoms of X1 may be between 6 and 14. The number of carbonatoms of Y1 may be between 6 and 14.

The polyamide A1 is manufactured using known techniques for theproduction of polyamides.

With regard to the plasticizer, this is chosen from benzenesulphonamidederivatives, such as N-butylbenzenesulphonamide (BBSA),ethyltoluenesulphonamide or N-cyclohexyltoluenesulphonamide; esters ofhydroxybenzoic acids, such as 2-ethylhexyl-para-hydroxybenzoate and2-decylhexyl-para-hydroxybenzoate; esters or ethers oftetrahydrofurfuryl alcohol, like oligoethoxylated tetrahydrofurfurylalcohol; and esters of citric acid or hydroxymalonic acid, such asoligoethoxylated malonate. Mention may also be made ofdecylhexyl-para-hydroxybenzoate and ethylhexyl-para-hydroxybenzoate. Oneparticularly preferred plasticizer is N-butylbenzenesulphonamide (BBSA).

With regard to the impact modifier, mention may be made, for example, ofpolyolefins, crosslinked polyolefins, EPR, EPDM, SBS and SEBSelastomers, it being possible for these elastomers to be grafted inorder to make it easier to compatibilize them with the polyamide,copolymers having polyamide blocks and polyether blocks. Thesecopolymers having polyamide blocks and polyether blocks are known perse—they are also called PEBAs (polyether-block-amides). Mention may alsobe made of acrylic elastomers, for example those of the NBR, HNBR orX-NBR type. Described in detail below are crosslinked polyolefins andthen polyolefins.

As regards the crosslinked polyolefins, this phase can originate (i)from the reaction of two polyolefins having groups which react with oneanother, (ii) from maleated polyolefins with a monomeric, oligomeric orpolymeric diamino molecule, (iii) or from one (or more) unsaturatedpolyolefin carrying unsaturation and which can be crosslinked, forexample, by the peroxide route. As regards the reaction of twopolyolefins, this crosslinked phase originates, for example, from thereaction:

-   -   of a product (A) comprising an unsaturated epoxide,    -   of a product (B) comprising an unsaturated carboxylic acid        anhydride,    -   optionally of a product (C) comprising an unsaturated carboxylic        acid or of an α,ω-aminocarboxylic acid.

As regards the crosslinked polyolefins, mention may be made, as examplesof product (A), of those comprising ethylene and an unsaturated epoxide.

According to a first form of the invention, (A) is either an ethyleneunsaturated epoxide copolymer or a polyolefin grafted by an unsaturatedepoxide.

As regards the polyolefin grafted by an unsaturated epoxide, the term“polyolefin” is understood to mean polymers comprising olefin units,such as, for example, ethylene, propylene, 1-butene or all otherα-olefin units. Mention may be made, by way of example, of:

-   -   polyethylenes, such as LDPE, HDPE, LLDPE or VLDPE,        polypropylene, ethylene/propylene copolymers, EPRs        (ethylene-propylene rubber) or else metallocene PEs (copolymers        obtained by single-site catalysis),    -   styrene/ethylene-butylene/styrene (SEBS) block copolymers,        styrene/butadiene/styrene (SBS) block copolymers,        styrene/isoprene/styrene (SIS) block copolymers,        styrene/ethylene-propylene/styrene (SEPS) block copolymers or        ethylene-propylene-diene monomer (EPDM) terpolymers;    -   copolymers of ethylene with at least one product chosen from        salts or esters of unsaturated carboxylic acids or vinyl esters        of saturated carboxylic acids.

Advantageously, the polyolefin is chosen from LLDPE, VLDPE,polypropylene, ethylene/vinyl acetate copolymers or ethylene/alkyl(meth)acrylate copolymers. The density may advantageously be between0.86 and 0.965 and the melt flow index (MFI) may be between 0.3 and 40(in g/10 min at 190° C./2.16 kg).

As regards the ethylene unsaturated epoxide copolymers, mention may bemade, for example, of copolymers of ethylene with an alkyl(meth)acrylateand with an unsaturated epoxide or copolymers of ethylene with asaturated carboxylic acid vinyl ester and with an unsaturated epoxide.The amount of epoxide may be up to 15% by weight of the copolymer andthe amount of ethylene at least 50% by weight.

Advantageously, (A) is an ethylene alkyl (meth)acrylate unsaturatedepoxide copolymer.

Preferably, the alkyl (meth)acrylate is such that the alkyl has 2 to 10carbon atoms.

The MFI (melt flow index) of (A) may, for example, be between 0.1 and 50(g/10 min at 190° C./2.16 kg).

Examples of alkyl acrylates and methacrylates that may be used are inparticular methyl methacrylate, ethyl acrylate, n-butyl acrylate,isobutyl acrylate and 2-ethylhexyl acrylate. Examples of unsaturatedepoxides that may be used are in particular:

-   -   aliphatic glycidyl esters and ethers, such as allyl glycidyl        ether, vinyl glycidyl ether, glycidyl maleate, glycidyl        itaconate, glycidyl acrylate and glycidyl methacrylate, and    -   alicyclic glycidyl esters and ethers, such as 2-cyclohexene-1-yl        glycidyl ether, diglycidyl cyclohexene-4,5-dicarboxylate,        glycidyl cyclohexene-4-carboxylate, glycidyl        5-norbornene-2-methyl-2-carboxylate and diglycidyl        endo-cis-bicyclo[2.2.1]hept-5-ene-2,3-dicarboxylate.

According to another form of the invention, the product (A) is a producthaving two epoxide functional groups, such as, for example, bisphenol Adiglycidyl ether (BADGE).

Mention may be made, as examples of product (B), of those comprisingethylene and an unsaturated carboxylic acid anhydride.

(B) is either an ethylene unsaturated carboxylic acid anhydridecopolymer or a polyolefin grafted by an unsaturated carboxylic acidanhydride.

The polyolefin may be chosen from the polyolefins mentioned above whichhave to be grafted by an unsaturated epoxide.

Examples of unsaturated dicarboxylic acid anhydrides that may be used asconstituents of (B) are in particular maleic anhydride, itaconicanhydride, citraconic anhydride and tetrahydrophthalic anhydride.

Mention may be made, as examples, of copolymers of ethylene, of an alkyl(meth)acrylate and of an unsaturated carboxylic acid anhydride andcopolymers of ethylene, of a saturated carboxylic acid vinyl ester andof an unsaturated carboxylic acid anhydride.

The amount of unsaturated carboxylic acid anhydride may be up to 15% byweight of the copolymer and the amount of ethylene at least 50% byweight.

Advantageously, (B) is a copolymer of ethylene with analkyl(meth)acrylate and with an unsaturated carboxylic acid anhydride.Preferably, the alkyl(meth)acrylate is such that the alkyl has 2 to 10carbon atoms. The alkyl(meth)acrylate may be chosen from those mentionedabove. The MFI of (B) may, for example, be between 0.1 and 50 (g/10 minat 190° C./2.16 kg).

It would not be outside the scope of the invention if a portion of thecopolymer (B) were to be replaced with an ethylene/acrylic acidcopolymer or an ethylene/maleic anhydride copolymer, the maleicanhydride having been completely or partially hydrolysed. Thesecopolymers may also comprise an alkyl(meth)acrylate. This portion mayrepresent up to 30% of (B).

According to another form of the invention, (B) can be chosen fromaliphatic, alicyclic or aromatic polycarboxylic acids or their partialor complete anhydrides.

Mention may be made, as examples of aliphatic acids, of succinic acid,glutaric acid, pimelic acid, azelaic acid, sebacic acid, adipic acid,dodecanedicarboxylic acid, octadecanedicarboxylic acid, dodecenesuccinicacid and butanetetracarboxylic acid.

Mention may be made, as examples of alicyclic acids, ofcyclopentanedicarboxylic acid, cyclopentanetricarboxylic acid,cyclopentanetetracarboxylic acid, cyclohexanedicarboxylic acid,hexanetricarboxylic acid, methylcyclopentanedicarboxylic acid,tetrahydrophthalic acid, endo-methylenetetrahydrophthalic acid andmethyl-endo-methylenetetrahydrophthalic acid.

Mention may be made, as examples of aromatic acids, of phthalic acid,isophthalic acid, terephthalic acid, trimellitic acid, trimesic acid orpyromellitic acid.

Mention may be made, as examples of anhydrides, of the partial orcomplete anhydrides of the above acids.

Use is advantageously made of adipic acid.

With regard to the product (C) comprising an unsaturated carboxylicacid, mention may be made, as examples, of the products (B) completelyor partly hydrolysed. (C) is, for example, an ethylene unsaturatedcarboxylic acid copolymer and advantageously an ethylene(meth)acrylicacid copolymer.

Mention may also be made of ethylene alkyl(meth)acrylate acrylic acidcopolymers. These copolymers have for example an MFI of between 0.1 and50 (g/10 min at 190° C./2.16 kg).

The amount of acid may be up to 10% by weight and preferably 0.5 to 5%.The amount of (meth)acrylate is for example from 5 to 40% by weight.

(C) may also be chosen from α,ω-aminocarboxylic acids, such as, forexample, NH₂—(CH₂)₅COOH, NH₂—(CH₂)₁₀COOH and NH₂(CH₂)₁₁—COOH andpreferably aminoundecanoic acid.

The proportion of (A) and (B) necessary to form the crosslinked phase isdetermined according to the usual rules of the art by the number ofreactive functional groups present in (A) and in (B).

For example, in the crosslinked phases comprising (C) chosen fromα,ω-aminocarboxylic acids, if (A) is an ethylene alkyl(meth)acrylateunsaturated epoxide copolymer and (B) an ethylene alkyl(meth)acrylateunsaturated carboxylic acid anhydride copolymer, the proportions aresuch that the ratio of the anhydride functional groups to the epoxyfunctional groups is in the region of 1.

The amount of α,ω-aminocarboxylic acid is then from 0.1 to 3% andpreferably 0.5 to 1.5% of (A) and (B).

As regards (C) comprising an unsaturated carboxylic acid, that is to say(C) being chosen, for example, from ethylene/alkyl(meth)acrylate/acrylicacid copolymers, the amount of (C) and (B) may be chosen so that thenumber of acid functional groups and of anhydride functional groups isat least equal to the number of epoxide functional groups and,advantageously, products (B) and (C) are used such that (C) represents20 to 80% by weight of (B) and preferably 20 to 50%.

It would not be outside the scope of the invention if a catalyst wereadded. These catalysts are generally used for the reactions between theepoxy groups and the anhydride groups.

Mention may in particular be made, among the compounds capable ofaccelerating the reaction between the epoxy functional group present in(A) and the anhydride or acid functional group present in (B), of:

-   -   tertiary amines, such as dimethyllaurylamine,        dimethylstearylamine, N-butylmorpholine,        N,N-dimethylcyclohexylamine, benzyldimethylamine, pyridine,        4-(dimethylamino)pyridine, 1-methylimidazole,        tetramethylethylhydrazine, N,N-dimethylpiperazine,        N,N,N′,N′-tetramethyl-1,6-hexanediamine or a mixture of tertiary        amines having from 16 to 18 carbons and known under the name of        dimethyltallowamine        -   1,4-diazabicyclo[2.2.2]octane (DABCO)        -   tertiary phosphines, such as triphenylphosphine        -   zinc alkyldithiocarbamates.

The amount of these catalysts is advantageously from 0.1 to 3% andpreferably 0.5 to 1% of (A)+(B)+(C).

As regards the noncrosslinked polyolefins, mention may be made of thepolyolefins described in the preceding section and intended to begrafted by reactive groups. Mention may also be made of the products (A)or (B) or (C) of the preceding section but used alone in order not tocrosslink.

With regard to the polyamide A2, this is a polyamide which is not theidentical as A1 but could be chosen in the same family of A1. Mentionmay be made of PA 11, PA 6 and PA 12. In a specific embodiment this is apolyamide containing a polycondensation catalyst, such as an organic ormineral acid, for example phosphoric acid. The catalyst may be added tothe polyamide A2 after it has been prepared by any process or quitesimply, and as is preferred, it may be the residue of the catalyst usedfor its preparation. The term “catalyzed polyamide” means that thechemistry will be continued beyond the steps for synthesizing the baseresin and therefore during the subsequent steps in the preparation ofthe compositions of the invention. Polymerization and/ordepolymerization reactions may very substantially take place during theblending of the polyamides A1 and A2 to prepare the compositions of thepresent invention. Typically, the Applicant believes (without being tieddown by this explanation) that polymerization is continued (by chainextension) and that the chains become branched (for example by bridgingvia phosphoric acid). In addition, this may be considered as a tendencytowards re-equilibration of the polymerization equilibrium, andtherefore a kind of homogenization. However, it is recommended that thepolyamides be thoroughly dried (and advantageously their moisturecontent properly controlled) in order to avoid any depolymerization. Theamount of catalyst may be between 5 ppm and 15000 ppm of phosphoric acidrelative to A2. The amount of catalyst may be up to 3000 ppm relative tothe amount of polyamide A2 and advantageously between 50 and 1000 ppm.In the case of other catalysts, for example boric acid, the contentswill be different and may be chosen appropriately depending on the usualtechniques for the polycondensation of polyamides. Advantageously, A2 ischosen from PA-11,PA 6 and PA-12.

With regard to the proportions of A1, of the plasticizer, of the impactmodifier and of A2, these may vary widely.

For example, to make compressed-air hoses useful in the brake circuitsof heavy goods vehicles, the plasticizer is (by weight) between 5 and20% (advantageously between 10 and 15%), the impact modifier between 0and 5%, the polyamide A2 between 0 and 5% and the balance made ofpolyamide A1. Preferably, A1 is PA-10,10 or PA6,y. This compositionexhibits good impact strength and burst strength after ageing.

For example, to make hoses useful in hydraulic clutch circuits forautomobiles and heavy goods vehicles, the plasticizer is (by weight)between 0 and 5%, the impact modifier between 0 and 5%, the polyamide A2between 0 and 35% and the balance made of polyamide A1. Preferably A1 isPA-6,y. These hoses have a high pressure resistance. The presence of A2makes it possible to increase the toughness and lifetime, but to thedetriment of the burst strength.

For example, to make hoses useful for conveying petrol or diesel fromthe motor-vehicle tank to the injection device and back, the plasticizeris (by weight) between 4 and 10% (advantageously between 4 and 8%), theimpact modifier between 5 and 15% (advantageously between 8 and 12%),the polyamide A2 between 10 and 20% (advantageously between 12 and 17%)and the balance made of polyamide A1. Advantageously, the impactmodifier is a crosslinked polyolefin. Advantageously, A1 is PA-6,y orPA-10,10 Advantageously, these hoses include other layers, such as thosemade of for example PA-6, a blend of PA-6 and a polyolefin having a PA-6matrix, EVOH, fluoropolymer, polyester, aliphatic polyketone or PPS.

With regard to the preparation of the compositions of the invention,these may be prepared by melt-blending the constituents using thestandard techniques for thermoplastics.

The compositions according to the invention may additionally include atleast one additive chosen from:

dyes;

pigments;

brighteners;

antioxidants;

fire retardants;

UV stabilizers;

nanofillers;

nucleating agents.

With regard to the multilayer structures, mention may be made of thefollowing:

-   Structure (a) comprising:    -   a layer of the composition of the invention and a layer of        another polyamide, a coextrusion tie possibly being placed        between them;-   Structure (b) comprising:    -   a layer of the composition of the invention between two        polyamide layers, a coextrusion tie possibly being placed        between two or more of these layers (by way of example mention        may be made of a layer of PA 11 or PA 12, a layer of the        composition of the invention, a layer of PA 6);-   Structure (c) comprising, in succession:    -   a layer of the composition of the invention, optionally a tie        layer, a layer chosen from fluoropolymers (for example PVDF),        PPS, EVOH, aliphatic polyketones and polyesters, optionally a        tie layer, and a layer of the composition of the invention;-   Structure (d) comprising, in succession:    -   a layer of the composition of the invention, optionally a tie        layer, a layer chosen from fluoropolymers (for example PVDF),        PPS, EVOH, aliphatic polyketones and polyesters, optionally a        tie layer, and a polyamide layer;-   Structure (e) comprising, in succession:    -   a layer of the composition of the invention, optionally a tie        layer, a layer chosen from fluoropolymers (for example PVDF),        PPS, EVOH, aliphatic polyketones and polyesters.

The above structures may be used for any fluids, including petrol anddiesel. In the above structures, one or more of the layers may containconducting substances in order to make them antistatic. In the abovestructures, it is possible to add a layer that contains conductivesubstances in order to render it antistatic and thus render thestructure antistatic. Advantageously, these structures are used to makedevices for transferring or storing fluids and advantageously the layermentioned first is the outer layer, the layer mentioned last is thelayer in contact with the stored or transported fluid. According to onepossible form, the layer in contact with the fluid takes the form of twolayers of the same composition except the one in contact with the fluid,which contains conductive substances in order to make it antistatic andthus render the structure antistatic. In the above structures and thosein the rest of the text, the conductor may be carbon black or carbonfibres or carbon nanotubes. It is advantageous to use a carbon blackchosen from those having a BET specific surface area, measured accordingto the ASTM D3037-89 standard, of 5 to 200 m²/g, and a DBP absorption,measured according to the ASTM D 2414-90 standard, of 50 to 300 ml/100g. This is described in Application WO 99/33908,the proportions ofcarbon black are in general between 17 and 30% by weight and preferablyaround 23-26%.

With regard more particularly to petrol, structures are used thatcomprise, in addition to a layer of a composition of the invention, oneor more layers chosen from PA-6, EVOH and PA-6/polyolefin blends havinga PA-6 matrix.

The PA-6 may include elastomers such as EPR or EPDM, or very low-densitypolyethylene, these products possibly being grafted by a functionalmonomer in order to make them compatible with the PA-6.

In a preferred embodiment the PA-6/polyolefin blends having a PA-6matrix comprise, the total being 100%:

50 to 90% (advantageously 60 to 80%) of PA-6;

1 to 30% (advantageously 10 to 25%) of HDPE; and

5 to 30% (advantageously 10 to 20%) of at least one polymer P1 chosenfrom impact modifiers and polyethylenes,

at least one of HDPE and P1 being completely or partly functionalized.

Advantageously, the impact modifier is chosen from elastomers and verylow-density polyethylenes.

With regard to the impact modifier and firstly to the elastomers,mention may be made of SBS, SIS and SEBS block polymers, andethylene-propylene (EPR) or ethylene-propylene-diene monomer (EPDM)elastomers. As regards the very low-density polyethylenes, these are,for example, metallocenes with a density of, for example, between 0.860and 0.900.

Advantageously, an ethylene-propylene (EPR) or ethylene-propylene-dienemonomer (EPDM) elastomer is used. The functionalization may be providedby grafting or copolymerization with an unsaturated carboxylic acid. Itwould not be outside the scope of the invention to use a functionalderivative of this acid. Examples of unsaturated carboxylic acids arethose having 2 to 20 carbon atoms, such as acrylic, methacrylic, maleic,fumaric and itaconic acids. The functional derivatives of these acidscomprise, for example, anhydrides, ester derivatives, amide derivatives,imide derivatives and metal salts (such as alkali metal salts) of theunsaturated carboxylic acids.

Unsaturated dicarboxylic acids having 4 to 10 carbon atoms and theirfunctional derivatives, particularly their anhydrides, are particularlypreferred grafting monomers. It is advantageous to use maleic anhydride.

The proportion of functionalized HDPE and/or functionalized P1 relativeto the combination of functionalized or unfunctionalized HDPE andfunctionalized or unfunctionalized P1 may be between 0 and 70%,advantageously between 5 and 60% and preferably between 20 and 60% byweight.

The PA-6/polyolefin blends having a PA-6 matrix may be prepared bymelt-blending the various constituents in machines commonly used in thethermoplastic polymer industry.

According to a first form of these PA-6/polyolefin blends having a PA-6matrix, the HDPE is not grafted and P1 is a grafted elastomer/ungraftedelastomer blend.

According to another form of these PA-6/polyolefin blends having a PA-6matrix, the HDPE is not grafted and P1 is a grafted polyethyleneoptionally blended with an elastomer.

In the PA-6/polyolefin blends having a PA-6 matrix, it would not beoutside the scope of the invention to replace the PA-6 completely orpartly with PA-6,10/Z of the invention. This is also valid in the caseof the structures given below.

By way of example, mention may be made of the following structures inwhich the inner layer is in contact with the petrol or diesel:

-   Structure (f) comprising, in succession from the outside inwards:    -   a layer of the composition of the invention (advantageously        PA-6,y), optionally a tie layer, a PA-6 layer or a layer of a        PA-6/polyolefin blend having a PA-6 matrix; optionally the inner        layer contains a conductor.-   Structure (g) Comprising, in Succession from the Outside Inwards:    -   a layer of the composition of the invention (advantageously        PA-6,y), optionally a tie layer, a PA-6 layer or a layer of a        PA-6/polyolefin blend having a PA-6 matrix, a PA-6 layer or a        layer of a PA-6/polyolefin blend having a PA-6 matrix and        containing a conductor;-   Structure (h) Comprising, in Succession from the Outside Inwards:    -   a layer of the composition of the invention (advantageously        PA-6,y), optionally a tie layer, a PA-6 layer or a layer of a        PA-6/polyolefin blend having a PA-6 matrix, an EVOH layer, a        PA-6 layer or a layer of PA-6/polyolefin blend having a PA-6        matrix;-   Structure (h1) Comprising, in Succession from the Outside Inwards:    -   a layer of the composition of the invention (advantageously        PA-6,y), optionally a tie layer, a PA-6 layer or a layer of a        PA-6/polyolefin blend having a PA-6 matrix, an EVOH layer, a        PA-6 layer or a layer of PA-6/polyolefin blend having a PA-6        matrix, a PA-6 layer or a layer of a PA-6/polyolefin blend        having a PA-6 matrix and containing a conductor;-   Structure (i) Comprising, in Succession from the Outside Inwards:    -   a layer of the composition of the invention (advantageously        PA-6,y), optionally a tie layer, a PA-6 layer or a layer of a        PA-6/polyolefin blend having a PA-6 matrix, an EVOH layer, a        PA-6 layer or a layer of a PA-6/polyolefin blend having a PA-6        matrix and containing a conductor;-   Structure (j) Comprising, in Succession from the Outside Inwards:    -   a layer of the composition of the invention (advantageously        PA-6,y), optionally a tie layer optionally containing an impact        modifier, an EVOH layer, a PA-6 layer or a layer of a        PA-6/polyolefin blend having a PA-6 matrix and optionally        containing a conductor;-   Structure (k) Comprising, in Succession from the Outside Inwards:    -   a layer of the composition of the invention (advantageously        PA-6,y), optionally a tie layer optionally containing an impact        modifier, an EVOH layer, a PA-6 layer or a layer of a        PA-6/polyolefin blend having a PA-6 matrix, a PA-6 layer or a        layer of a PA-6/polyolefin blend having a PA-6 matrix and        containing a conductor; and-   Structure (l) Comprising, in Succession from the Outside Inwards:    -   a layer of the composition of the invention (advantageously        PA-6,y), optionally a PA-6 layer or a layer of a PA-6/polyolefin        blend having a PA-6 matrix, an EVOH layer, optionally a PA-6        layer or a layer of a PA-6/polyolefin blend having a PA-6        matrix, a layer of the composition of the invention        (advantageously PA-6,y) optionally containing a conductor.

In structures (j) and (k), the tie may be a copolyamide or a blend ofcopolyamides, and it optionally contains an impact modifier (for examplean optionally grafted EPR or EPDM).

EXAMPLES Example 1 Plasticized PA-10,10 for Compressed-Air BrakeApplications

Composition: PA-10,10 (86.4%) +13% BBSA+0.6% Polyad PB201.

Polyad PB201 denotes an inorganic antioxidant based on copper iodide.

This formulation was tested and compared with the values of the DIN73378 PHLY standard. The moduli were evaluated on the injection-mouldedmaterial and the burst strength and impact strength values wereevaluated on an extruded tube with inside/outside diameters of 6 and 8mm. The table below shows that the plasticized PA-10,10 meets thisstandard as regards modulus, burst strength and impact strength afterageing. The value of the burst strength at 140° C. is greater than therequirements at 130° C.

Property Standard Value DIN 73378 PHLY Tensile modulus after ISO 527 550450-600 moulding (MPa) Flexural modulus after ISO 178 480 conditioning*(MPa) 23° C. burst DIN 73378 30 >27 strength (MPa) 100° C. burst DIN73378 14.5 >0.43* (23° C. strength (MPa) value) = 12.9 130° C. burst DIN73378 10.5 >0.31* (23° C. strength (MPa) value) = 9.3 140° C. burst DIN73378 9.5 strength (MPa) −40° C. impact DIN 73378 0 breaks No breaks atstrength on tube after in 10 23° C. 72 h at 150° C. *conditioning at 23°C./50% RH for 15 days.

Example 2

PA-6,10 and PA-6,12 for hydraulic (clutch) pipe applications. In thetable below the proportion of polyamide represents the balance to 100%.PA-11 denotes a catalyzed PA-11 containing 600 ppm of phosphoric acid.

PA-6,12 + PA-6,10 + PA-6,12 + 30% PA-11 + PA-6,10 + 30% Pa11 + 0.6%Polyad 0.6% Polyad 0.6% Polyad 0.6% Polyad PA-12 T6L Standard PB201PB201 PB201 PB201 black AESN Flexural modulus (MPa) ISO 178 1500 10301220 1010 1280 Tensile modulus (MPa) ISO 527 2030 1470 1840 1490 150023° C. burst DIN 73378 55 40 54 44 47 strength (MPa) 140° C. burst DIN73378 14 10 16 12 9.5 strength (MPa) (12 MPa at 120° C.) 23° C. CharpyISO 179 7 11 9 13 15 notched impact strength (kJ/m²) −40° C. Charpy ISO179 5.5 8 6.5 10.5 8 notched impact strength (kJ/m²) Half-life/140° C.Atofina 250 >1200 900 >1200 2500 thermal ageing method* in air (hours)*time after which the elongation of the test piece is reduced by afactor of 2 relative to the initial value (injection-moulded testpiece).

The above table shows that the PA-6,10 and the PA-6,12 may beadvantageously used instead of PA-12 for a hydraulic application, wherehigh pressure resistance is necessary (for example, for a clutch fluidtube). PA-6,10 has advantages in terms of hot burst strength, impactstrength and high-temperature ageing compared with PA-6,12. The additionof PA-11 increases the toughness and the lifetime, but to the detrimentof the burst strength.

Example 3 Multilayer for a Petrol Line

The following tubular structures with an inside diameter of 6 mm and awall thickness of 1 mm were produced using the following products:

-   PA-6,10 denotes a PA-6,10 comprising 10% of a crosslinked phase LT,    15% of catalyzed PA-11 containing 600 ppm of phosphoric acid, 5% of    BBSA and 0.6% of Polyad PB201 (the total being 100%). The    crosslinked phase LT results from blending:    5% Lotader® 4700+2.5% Lotader® AX8900+2.5% Lucalen(® A 3110M.-   Lotader® 4700 is an ethylene/ethyl acrylate/maleic anhydride    copolymer containing 30% acrylate by weight and 1.5% MAH, and having    an MFI of 7g/10 min at 190° C./2.16 kg. Lotader® AX8900 is an    ethylene/methyl acrylate/glycidyl methacrylate copolymer containing    25% acrylate and 8% GMA by weight and having an MFI of 6 g/10 min at    190° C./2.16 kg. Lucalen® A 3110M denotes an ethylene/butyl    acrylate/acrylic acid copolymer having an 88/8/4 composition by    weight (sold by BASF).-   Conductive PA-6,10 denotes the above PA-6,10 to which an amount of    carbon black is added so that the black content is 22% by weight    relative to the weight of conductive PA-6,10. Its surface    resistivity is between 10² and 10⁶ ohms/measured using the SAEJ2260    standard.-   EVOH32 denotes an EVOH copolymer containing 32 mol % ethylene, sold    under the name Soarnol® DC3203F by Nippon Goshei.-   EVOH44 denotes an EVOH copolymer containing 44 mol % ethylene sold    under the name Soarnol® AT4403 by Nippon Goshei.-   Orgalloy® denotes a 70% PA-6/15% HDPE/15% grafted EPR blend, which    also contains antioxidants.-   Conductive Orgalloy® denotes the previous Orgalloy® to which an    amount of carbon black is added so that the black content is 22% by    weight relative to the weight of conductive Orgalloy®. Its surface    resistivity is between 10² and 10⁶ ohms/measured according to the    SAEJ2260 standard.-   The carbon black was supplied by 3M under the name “Ensaco 250    Granular”; the DBP absorption is 190 ml/g and the BET surface area    about 65 m²/g.-   Structure 1: PA-6,10 (500 μm) outer layer/Orgalloy® (500 μm);-   Structure 2: PA-6,10 (500 μm) outer layer/Orgalloy® (400    μm)/conductive Orgalloy® (100 μm);-   Structure 3: PA-6,10 (375 μm) outer layer/Orgalloy® (100 μm)/EVOH32    (100 μm)/Orgalloy® (425 μm);-   Structure 4: PA-6,10 (375 μm)/Orgalloy® (100 μm)/EVOH32 (100    μm)/Orgalloy® (325 μm)/conductive Orgalloy® (100 μm);-   Structure 5: PA-6,10 (350 μm)/Orgalloy® (100 μm)/EVOH32 (100    μm)/Orgalloy® (100 μm)/conductive PA-6,10 (350 μm); and-   Structure 6: PA-6,10 (350 μm)/EVOH44 (300 μm)/conductive PA-6,10    (350 μm).

The PA-6,10 is resistant to zinc chloride. This type of line cantherefore be used under the chassis of motor vehicles.

Structures 3 to 6 have a markedly lower permeability to petrolcontaining ethanol than the polyamide nylon-6,10 alone.

Structures 1 and 2 have a reduced permeability and excellent temperatureresistance, the melting point of PA-6,10 and of Orgalloy® being 220° C.

Structures 2, 5 and 6 have a conductive internal layer, which makes itpossible to remove any static electricity generated by friction of thepetrol on the polymer.

The advantage of these structures is the absence of a tie between thepolyamide nylon-6,10 and the Orgalloy®, and the use of Orgalloy® as atie between the PA-6,10 and the EVOH. The same structures have also beenproduced, but with PA-6,12 instead of PA-6,10. The peel force needed toseparate the PA-6,10 or the PA-6,12 from the Orgalloy® is greater than50 N/cm (25 mm/min peel at room temperature).

Structure 6 was produced without an Orgalloy® layer between the PA-6,10and the EVOH. To have sufficient adhesion, it is necessary in this caseto use an EVOH with a high ethylene content. Structures 3 and 4 may beproduced in the same way with the Orgalloy® and EVOH 32 internal layersreplaced with a single layer of Soarnol AT4403.

Example 4

The following table shows that the flexural modulus can be lowered verysignificantly with this type of formulation, while still maintaininggood thermomechanical properties and excellent ageing. In this table,“LT” and “PA-11” have the same meanings as in Example 3. The PA-6,10exhibits interesting behaviour compared with the PA-6,12 with the sameformulation: lower modulus but higher high-temperature burst strength.These materials may be used as petrol or diesel lines made of amonolayer or multilayer tube (Example 3).

PA-6,12 + 10% LT + PA-6,10 + 10% LT + PA-10,10 + 10% LT + 15% PA-11 + 5%BBSA + 15% PA-11 + 5% BBSA + 15% PA-11 + 5% BBSA + Formulations Standard0.6% Polyad PB201 0.6% Polyad PB201 0.6% Polyad PB201 Flexural modulus(MPa) ISO 178 590 505 390 Tensile modulus (MPa) ISO 527 790 755 505 23°C. burst DIN 73378 31 31 25 strength (MPa) 140° C. burst DIN 73378 9.510.5 7 strength (MPa) −40° C. Charpy notched ISO 179 7.5 8 5.5 impactstrength (kJ/m²) Half-life/140° C. thermal Atofina >1200 >1200 >1200ageing in air (hours) method* *time after which the elongation of thetest piece is reduced by a factor of 2 relative to the initial value(injection-moulded test piece).

1. A composition comprising, by weight, the total being 100%: 50 to 100%of at least one polyamide A1 of formula X.Y/Z or 6.Y2/Z in which: “6”denotes the residues of hexamethylene diamine, X denotes the residues ofan aliphatic diamine having from 6 to 10 carbon atoms, Y denotes theresidues of an aliphatic dicarboxylic acid having from 10 to 14 carbonatoms, Y2 denotes the residues of an aliphatic dicarboxylic acid havingfrom 15 to 20 carbon atoms and Z denotes at least one unit chosen fromthe residues of a lactam, the residues of an α,ω-aminocarboxylic acid,the unit X1, Y1 in which X1 denotes the residues of an aliphatic diamineand Y1 denotes the residues of an aliphatic dicarboxylic acid, theweight ratios Z/(X+Y+Z) and Z/(6+Y2+Z) being between 1 and 15%; 4-10% ofa plasticizer; 5-15% of an impact modifier; and 10-20% of a polyamideA2.
 2. The composition according to claim 1, wherein the plasticizercomprises between 4 and 8% by weight, the impact modifier comprisesbetween 8 and 12% by weight, and the polyamide A2 comprises between 12and 17% by weight.
 3. The composition according to claim 1, wherein theimpact modifier is a crosslinked polyolefin.